Method of and apparatus for screening



D33. M. P. REYNOLDS ET AL 1,983,676

METHOD OF AND 'APPARATUS FOR SCREENING Filed Dec.,8, 1931 2 Sheets-Sheet2 I N VEN TOR 5 War/l3! Each fig vaidhid wiiace cli /9'70 ATTORNE 6;

Patented Dec. 11, 1934 INITED STATES.

METHOD OF AND APPARATUS FOR SCREENING Morley Punshon Reynolds, ClevelandHeights, and Wallace J. Piggott, East Cleveland, Ohio, assignors to TheW. 8. Tyler Company, Cleveland, @1110, a corporation of Ohio ApplicationDecember a, 1931, Serial No. 579,724

2 Claims.

The present invention, relating. as indicated, to

a method of and apparatus for screening materials, is more particularlydirected to a new and improved method of screening or classifying bothfine and coarse bulk materials and to an apparatus particularly adaptedfor economic, rapid and accurate separation of this type of material bysize. The principal object of the invention is the provision of a methodof and apparatus for handling bulk materials which will be extremelyeflicient in operation, capable of high tonnage capacity, extremelyaccurate, capable of operating with a low angle of screen surface,adaptable to give various motions and vibrations to the screen anduniform in its adaptability to various sizes'of material. A furtherobject of the invention is the provision of a method of and apparatusfor the purpose described which will be low in initial cost andeconomical in the foregoing and related ends, said invention, then,consists of the means hereinafter fully described and particularlypointed out in the claims.

' The annexed drawings and the following description set forth in detailcertain means and one mode of carrying out the invention, such disclosedmeans and mode illustrating, however, but one of various ways in whichthe principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a side view partially in section of a screening apparatusembodying my improved apparatus, and capable of carrying out the'stepsof my new and improved method; Fig. 2 is a plan view of such apparatus;Fig. 3 is a transverse sectional view of theapparatus illustrated inFig.

2, taken on a plane substantially indicated by the line 3-3; Fig. 4 is aside elevational view,

partially in section, of an apparatus similar to Fig. 1, but showing analternative form of construction; Fig. 5 is a fragmentary sectional viewdrawn to an, enlarged scale of a modified form of a portion of theapparatus illustrated in the previous figures; and Figs. 6 and 7 arefragmentary part-sectional, part-elevational views showing furthermodifications.

Screens now in general commercial use fall into a few well definedclasses. On'such screens,

the electro-magnetically vibrated woven wire screen is the mostefficient and is the most widely used for the screening of allrelatively fine materials and is extremely efiicient and economical inoperation in this field. For the screening of heavy materials, mechanismemploying either 5 5 tensioned woven wire screens which are vibrated useof power, etc. To the accomplishment ofthe and are high in their cost ofmaintenance, but

are in fairly common use for the classifying of heavy and coarsematerials.

' The present invention has been designed to provide a methodand anapparatus for relatively universal use and one which may be employed forscreening both fine and coarse materials with a minimum consumption ofpower and a minimum of upkeep, and with an effective vibration of thescreen surface, which is uniform throughout its entire area andsuficient in amplitude and intensity to effectively screen the coarse aswell as the fine materials.

Referring now to Fig. 1, we have shown a side view, partially insection, of an inclined screen, the apparatus'consisting of a box-likecasing l pivotally mounted upon a suitable support 2 and adjustable withrespect to-its angle to the horizontal by any suitable means, not shown.With in this casing there is mounted the usual woven wire screen and asso far described, the apparatus employed is relatively standard.

The principal difficulty in the adaptation of the electro-magneticallyvibrated screen to coarse materials is in securing a sufiicientamplitude and intensity of vibration, and, while this can be secured, itrequires the use of extremely heavy, powerful electro-magnets, the sizeof which has to be increased out of all proportion to the remainder ofthe apparatus. A further limitation in the use of electro-magneticvibrating apparatus heretofore in use has been that, while efiective tosecure a suflicient amplitude in the central portion of the screen, thismovement of the screensuriace diminishes toward the edges of the screen,which are therefore not in a state or vibration permitting them toefiectively screen material or to prevent clogging and blinding,particularly with certain types of material which it is desired toscreen.

Our new and improved screening method consists in passing a layer ofscreenable bulk material over an inclined woven wire screen which istensioned to a. vibratory tension throughout its entire screen surface,but which is floated and resilan effective use of the entire area of thescreen and thus impart to the screen a relatively rapid,

cure the ready tron of this vibration throughout the screen surface. InFigs 1, 2 and v3, we have shownone form of apparatus which embodies ourinventionand which is capable of carrying out thesteps of the methodstated -'above.

- nevertheless itis to be understood that any suitable number dependingupon the type and size of screen cloth may be employed for the purposeof vibrating such cloth. The electro-magnetic vibrators 5 have theirarmatures secured to U-shaped brackets 6 which, in turn, are secured toa strip or plate engaged with the woven wire screen 4.

Mounted on the parallel side members 2 and 3 are a series of studs 8extending at right angles to the longitudinal axis of the frame and thescreen, and carrying at their ends hook members 9, abutment portions ofwhich are adapted to be engaged by the rebent hook-shaped strips 10 towhich the screen may be secured. The studs 8 at their outer ends carryseat members 11 and nuts 12, and compression springs'13 are interposedbetween the seat members and the side frame members 2 and 3 to permit ofthe application of any desired lateral tension to the screen. The studs8 are not fixed in the frame members 2 and 3, but are movably mountedtherein and pass through openings larger than the studs, permittingangular movement by the studs as required.

In order to insure against the passage of unclassified material betweenthe edge of the screen and the inner faces of the side frame members 2and 3, baille members is are provided which are preferably of suitableresilient material and are supported from such side frame members 2 and3 by angle brackets 15.

As previously indicated, the number of vibrators employed may be variedto suit the particular requirements of the cloth being operated upon, aswell as the material which is to be screened. Three arm-senators may beemployed, or any desired number to produce the desired results.

, In Fig. 4 are shown vibrators 5a, mounted at an angle to the screensurface and secured through angle brackets 15 to the screen strip. Inthis construction the screen is not vibrated in a straight up-and-downplane at right angles to the normal surface of the screen cloth, but ina plane at" acute angles to the normal screen surface, giving the screena vibration having components both longitudinally and at right-angles toits surface, thus securing a motion of the screen surface which may beemployed depending upon the angle and inclination of the vibrators toeither hasten the flow over the screen, or to retard such flow.

As the movement of the material .can in this way be hastened, it ispossible to. operate the screen at a lower angle than in ordinary typesof screening apparatus, which will not only require intense vibration atpoints most eflective to seless head room for the apparatus, but whichwill maintain the material in contact with the screen for a greaterperiod, and thus more accurately separate the material by size as itwill prevent rapid rolling or bouncing of the material over the screen.In Fig. 6 is illustrated a modified form on con.- struction for engagingand supporting the sides of the screen cloth by the studs which carrythe compression springs. As illustrated in this fits ure, the stud-16 isprovided with a hook-shaped terminal 1'7 which engages around either oneof the wires of the screen cloth, or a slightly larger rod 18 which maybe welded to the body of the cloth or woven therein. The studs 16likewise pass through enlarged apertures 19 provided therefor in theside frame members 2 or 3, and

terminally carry a nut 20 and seat member 21 by means of which thecompression of the spring 22 can be regulated and, accordingly, theamount of the tension imparted thereby to the screen may be accuratelyadjusted.

In Fig. 5 is illustrated a further modification of the means forsupporting the screen cloth which may briefly be described as follows:Two screen cloths 23 and 24 respectively, are superimposed' one abovethe other and the mesh of the former. will preferably be larger than themesh of the latter, which determines the fineness of the material whichwill be classified. The upper screen cloth 24 is supported on the lowerby means of strips 25 which have certain forms of construction made ofsuitable resilient material, such as rubber, and for other forms of.construction materials such as asbestos, wood, and the like, may

be employed.

The lower cloth 23 is supported and tensioned by apparatus similar tothat employed for the purpose of supportingthe screen cloth in Fig. 3.Hence, like reference characters having prime marks will beemployed forthe purpose of designating like parts in this figure, and a furtherdescription of this apparatus will not be given.

The upper screen cloth 24 is supported and tensloned by means of abracket member 26 which has an abutment 2'7 engaging the hook stripalong the edge of the cloth and has a heel portion 28 bearing againstthe inner surface of the side frame member 2. The angle bracket 26, andaccordingly the screen cloth 24 supported thereby, is

cloth with a very much heavier and coarser cloth,

and in this way securing a much sharper and more intense vibration ofthe lighter cloth with-' out the wear which is usually incident tocontact between two such woven wire screens. In the past, light screenshave frequently been supported by heavier screens, but therelative'movement between the two screens rapidly wears the light screenand necessitates frequent replacement.

In Fig. 'I is illustrated a diflerent form of construction forresiliently supporting the screen cloth, so that the screen-is supportedin freely vibratory condition throughout its entire area, such meanscomprising bracket members, gener-' ally indicated at-8l, an angularlymoves about its fulcrum abutment 32 arranged for engagement by the hookstrip along the edge of the screen cloth, an upwardly extending portion33 providing an abutment for securing a packing strip 34.

The bracket, generally indicated at 31, is rigidly secured to a flexiblestud 35, which, at its outer end 36, is adjustably rigidly supported ina saddle 37 provided therefor, such saddle being mounted on, and carriedby the side frame members 2 or 3.

This modified construction, it will be noted, permits the screensupported and tensioned thereby to freely oscillate or vibrate over itsentire area, due to the resilient characteristics of the studs 35supporting thecloth. Any number of such studs may be employed, dependingupon the character of the cloth supported thereby, as well as thecharacteristics of the material to be treated. The studs 35 pass throughenlarged apertures in the side frame members so that the only point atwhich they are arrested is at their points of support on the saddle 3'2.

The present invention presents many advantages over the prior methodsof'screening. Our new method permits the screen surface to beeffectively. vibrated throughout its entire area and to be vibrated insuch a way as to give an angular impulse to the screen instead of animpulse at right angles to the normal plane of the screen surface. Anadditional advantage is that the free floating of the edges of thescreen permit the entire screen surface to be vibrated and remove thetendencyto cramp the armature and hence, to allow the electro-magnet toassume its full normal stroke, and to impart this strokeun- Y diminishedto the screen where the movement is fact that the electro-magneticmethod and means of vibration, which is admittedly the most eflectivefor the screening of fine materials can, by our improved method, beemployed for the screen-- ing of both fine and coarse materials withgreatly improved results in the screening of coarse materials and withadvantages in both tonnage and separation in the screening of finematerials.

Other modes of applying the principle of our invention may be employedinstead of the one explained, change being made as regards the means andthe steps herein disclosed, provided those stated by any of thefollowing claims or their equivalent be employed.

We therefore particularly point out and distinctly claim as ourinvention:

1. An apparatus of the character described, the combination of a frameincluding spaced sidemembers, spaced woven wire screens disposedbetweensaid side members, means for fioatingiy supporting one of saidscreens to maintain the whereby vibration is imparted to theotherthrough said supporting means.

2. An apparatus of the character described, the

combination of a frame including spaced side members; spaced woven wirescreens disposed between said side members, the lower of said screens oflarger mesh and stronger wires; means for floatingly supporting said.lower screen to maintain the same in freely vibratory conditionthroughout its entire area; means for supporting the upper screen on thelower; and means for imparting vibration to said lower screen wherebyvibration is imparted to the upper screen through said supporting means.

. MORLEY PUNSHON REYNOLDS.

WALLACE J. PIGGOTI.

